High lift mechanism

ABSTRACT

A high lift mechanism for trucks comprised generally of a scissors-type of lever mechanism which may be mounted to any standard truck chassis without extending below the channel beams of said chassis. Hydraulic cylinder means, normally laying almost flat in the chassis frame, first pushes against the top end of a pivoted link resulting in vertically directed forces to accomplish the first phase of the lift cycle. Roller means, carried by the head of the hydraulic cylinder piston, move along a bearing plate during the first portion of the lift cycle and when said roller means contacts abutment means at the end of the bearing plate, forces are directed thereagainst to accomplish the final phase of the lift cycle.

United States Patent 1 Traficant June 24, 1975 HIGH LIFT MECHANISM [76] lnventor: Charles Traficant, 1350 NW, 42nd Ave., Miami, Fla. 33126 22 Filed: Feb. 14,1973

211 Appl. No.: 332,516

[52] US. Cl. 214/512; 254/122 [51] Int. Cl. B60p l/02 [58] Field of Search 214/512; 254/122, 8 C, 254/124; 187/18 [56] References Cited UNITED STATES PATENTS 2,501,001 3/1950 Neely 254/122 2,706,102 4/1955 Cresci 254/122 X 2,928,558 3/1960 Bamford et a1. 1 254/8 C 3,259,369 7/1966 Gridley 254/122 FOREIGN PATENTS OR APPLICATIONS Australia 254/122 Primary ExaminerAlbert J. Makay [57] ABSTRACT A high lift mechanism for trucks comprised generally of a scissors-type of lever mechanism which may be mounted to any standard truck chassis without extending below the channel beams of said chassis. Hydraulic cylinder means, normally laying almost flat in the chassis frame, first pushes against the top end of a pivoted link resulting in vertically directed forces to accomplish the first phase of the lift cycle. Roller means, carried by the head of the hydraulic cylinder piston,

move along a bearing plate during the first portion of I the lift cycle and when said roller means contacts abutment means at the end of the bearing plate, forces are directed thereagainst to accomplish the final phase of the lift cycle.

8 Claims, 4 Drawing Figures HIGH LIFT MECHANISM STATE OF THE PRIOR ART U.S. Pat. No. 2,412,158 to N. V. Kuehlman et al. discloses a scissors type of high lift truck mechanism which is directed primarily to providing auxiliary wheels on the freight body to permit the truck proper, that is, the frame and cab, to be withdrawn from the freight body. The scissors type of levers employed are pivotally connected intermediate their lengths and links are pivotally connected to one end of each lever to eliminate the need for rollers in top and bottom tracks. A portion of the mechanism of this device extends below the truck chassis and the piston head is pivotally connected to the lever mechanism to function as a straight push-type through the entire lift cycle.

U.S. Pat. No. 2,935,218 to C. M. Fritz also discloses a scissors type of high lift truck mechanism which includes pivotally connected levers and a hydraulic cylinder, mounted well below the chassis, which provides a straight push system.

Another type of scissors type of elevating device is disclosed in U.S. Pat. No. 2,945,551 to M. H. Annin et al. Three sets of hydraulic power devices are employed, one pushes vertically, directly on the scissors, the second is longitudinally disposed in the chassis frame and the third is similarly disposed in the elevator platform. The second and third hydraulic devices exert longitudinally directed forces on the ends of the top and bottom scissors levers.

U.S. Pat. No. 3,220,585 to D. N. McCartney et al discloses a high lift trailer employing scissors type of levers, pivotally connected intermediate their lengths. Six hydraulic rams are utilized to lift the load carrying bed. Four small rams are positioned adjacent the four corners of the device to initiate the lifting operation and two large rams are utilized to complete the lift cycle.

BACKGROUND OF THE PRESENT INVENTION The present invention pertains to a compound linkage, high lift mechanism to elevate the cargo body of the truck to a degree whereby the cargo may be directly transferred to a cargo plane, for example.

One of the principal objects of the present invention is to provide a high lift mechanism that provides no elements extending below the upper flanges of the main beam members of a truck chassis. In this manner the high lift device may be bolted to the top flanges of the chassis beams, requiring only the drilling of appropriate holes therethrough.

Upper and lower, generally rectangular shaped frames are provided, the lower frame being fixed to the truck chassis with the upper frame normally having a cargo body fixed thereto. Two pairs of scissors type levers interconnect the respective sides of the upper and lower frames. A single hydraulic lift system serves to elevate the upper frame and the cargo body from a lower position of contact against the top of the lower frame to a fully elevated position. For heavy loads, the hydraulic lift system preferably incorporates a pair of cylinder assemblies operating in tandem.

Another principal jbject of the present invention is to provide a device which is a combination of two lift mechanisms, timed together, with an interlocked mechanical transfer of the lifting force from one mechanism to the other. This transfer of lifting forces is captive and cannot get out of timing or synchronization.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational view of the high lift mechanism of the present invention with the cargo body carrying frame in its fully retracted position;

FIG. 2 is a view similar to FIG. 1 with the frame elevated to an intermediate position;

FIG. 3 is a view similar to FIGS. 1 and 2 with the frame fully elevated; and

FIG. 4 is a cross sectional view taken along line 44 of FIG. 3.

DETAILED DESCRIPTION OF THE DRAWINGS With reference to the drawings in which like reference characters designate like or corresponding parts throughout the various views, the numerals 10 and 12 generally indicate the lower and upper frames. The lower frame 10 is comprised generally of a pair of side, inwardly turned channel rails 14 and 16 which are connected by one or more transverse members such as 18 and 20.

The upper frame 12 may be quite similar in construction but in any event includes a pair of side, inwardly turned channel rails 22 and 24. As fragmentarily illustrated at 26, a cargo body is fixed in any conventional manner atop the upper frame 12. Two pairs of scissors type levers 28, 30 and 32, 34 interconnect the lower and upper frames 10 and 12 adjacent to the side edges thereof.

As best illustrated in FIGS. 2 and 3, the first end of the lever 30 is pivotally connected at 36 to the lower frame channel rail 14 adjacent one end thereof. From the pivot 36, the lever 30 extends angularly, upwardly toward the opposed end of the device and carries a roller 38 on its second end which tracks within the upper channel rail 22.

The first end of the lever 28 is pivotally connected at 40 to the upper frame channel rail 22 in a position vertically above the pivot 36. From the pivot 40, the lever 38 extends angularly downwardly toward the opposed end of the device and carries a roller 42 on its second end which tracks within the lower channel rail 14. In this manner, the two levers 28 and 30 cross in scissors fashion and are pivotally attached at 44, intermediate their lengths. v

The above description of the levers 28 and 30 has been in the singular, however, it should be understood that the levers 32 and 34 are exact duplicates of, and function with, the levers 28 and 30.

One pair of opposed side levers 30 and 34 are rigidly spanned by a bearing plate 46 which is connected to said levers 30 and 34 by outer and inner plate members 48 and 50. A hydraulic cylinder 52 is pivotally attached at 54 to the transverse member 18 and provides a telescoping ram or piston 55 having a roller 56 on its outer end for engagement against the underside of the bearing plate 46. The roller shaft 58 may extend outwardly to both sides and carry additional rollers as indicated at 60 and 62.

A link 64 is pivotally attached at its lower end, as at 66, between the lower channels 14 and 16, and includes a yoke end 68, normally engaging the piston roller 56. A spring loaded piston assembly '70 is pivotally attached at 72 between the bottom channels 14, I8 and a point 74, intermediate the length of link 64, to main- It should be noted that, in practice, two hydraulic ram assemblies are positioned in a side-by-side relation and operate in tandem. The number of such ram assemblies is determined by the amount of weight to be lifted. It should also be understood that various other modifications, changes and arrangement or positioning of elements such as the bearing plate, rollers 56, 60 and 62, and link 64 can be made without departing from the basic principle of providing a combination of two lift mechanisms, timed together, with an interlocked mechanical transfer of lifting forces from one mechanism to another as will be apparent from the following description of the lift operation.

In use, the lower frame is bolted to the main chassis beams 80 of a track. Referring first to FIG. 1, it should be noted that all of the mechanism is contained within the confines of the upper and lower channel beams 14, 16 and 22, 24 when in the rest or fully retracted position.

The first part of the lifting mechanism defines a triangle A, B, C, with its three corners comprising the pivots 54, 56 and 66. In this position (FIG. 1) the hydraulic piston assembly is the triangle side AB. Attached to the end of the piston rod is the roller 56 which bears against the bottom of the bearing plate 46. This roller is also contained in the yoke 68 and the link 64 forms triangle side BC. Side AC is the base of the ABC triangle. Points AC are fixed and never move from their original positions. When hydraulic forces are applied to extend the piston 55, point B which is the roller moves along the underside of the bearing plate 46 while being confined in the yoke. The resulting forces at point B are straight up and in yielding to these forces, point B moves along an upwardly angled path because of the continued extension of the piston rod 55 and its engagement with the bearing plate 46.

FIG. 2 illustrates the extent of upward movement of the top frame 12 by the initial forces applied to the mechanism defined by the triangle ABC. As FIG. 2 illustrates, point B has contacted an abutment 82 formed by the inner plate member 50. Point B is now lifted from the yoke 68 and continues to move upwardly from the intermediate position of FIG. 2 to the position of FIG. 3 where the cargo body has been lifted to its fully elevated position.

As the cargo body proceeds from the position shown in FIG. 2 to that shown in FIG. 3, the mechanism defined by the triangle ABC ceases to exist as a working assembly and the force triangle is now made up of points ABD.

The return of mechanism to its At Rest position is a reverse of its upward cycle. When the upper frame 12 reaches of the the position shown in FIG. 2, the roller 56 reseats in the yoke 68 and all of the elements then return to the position of FIG. 1.

In the above description, the roller 56 is described as seating in the yoke 68 while, in fact, other rollers such as 60 and 62 will accomplish the same end result if the shaft 62 seats in a smaller yoke. It is only necessary to confine the path of travel of B along the bearing plate until some element carried by the end of the piston rod contacts the abutment 82.

What is claimed is:

l. A high lift mechanism, for mounting on a truck chassis, to move a cargo body fixed thereto between a retracted, down position and an elevated position comprising,

A. a lower'frame for fixed engagement with the truck chassis;

B. an upper frame to carry the cargo body threatop;

C. lever means interconnecting said frames comprised of,

1. a first combination of levers, and 2. a second combination of levers;

D. fluid actuated ram means for moving said upper frame between said positions;

E. means to drivingly engage the extended end of said ram means to said first combination of levers to elevate said upper frame to a predetermined, intermediate, level, in a first phase operation, when pressurized fluid is delivered to said ram means;

F. means to disengage said means to engage from said first combination of levers at said intermediate level and to simultaneously engage same with said second combination of levers to elevate said upper frame to its maximum elevated position in a second phase of operation;

said interconnecting lever means includes a pair of scissors type lift levers interconnecting each of the respective sides of said upper and lower frames and a link means pivotally attached at a first end to said lower frame, intermediate the opposed ends of said scissors levers; said scissors levers and link means comprising said first combination of levers and said scissors levers comprising said second combination of levers;

said means to drivingly engage comprises a bearing plate, fixed to and spanning a portion of one corresponding pair of said scissors levers, and a yoke means at the second end of said link means to receive a tip end portion of said ram; said bearing plate being sized and positioned to maintain said tip end portion in said yoke through said first phase of operation during which forces are directed upwardly by the movement of the ram and the resulting pivotal movement of said link means.

2. A high lift mechanism as defined in claim 1 wherein said means to disengage comprises abutment means fixed to and extending between said bearing plate and said corresponding pair of scissors levers, said abutment means being arranged and positioned to contact the tip end portion of said ram at the end of said first phase, resulting in disengagement of said tip end from said yoke, continued operation of said ram resulting in said second phase of operation during which lifting forces are directed to said upper frame by the scissors levers.

3. A high lift mechanism as defined in claim 1 including roller means, carried by said tip end portion, in bearing engagement between said yoke and bearing plate.

4. A high lift mechanism as defined in claim 1 including a spring loaded piston means connecting between said lower frame and link means.

5. A high lift mechanism as defined in claim 1 wherein the side rails of said upper and lower frames are formed of channel beams, each of said scissors levers having a first end pivotally attached to one of said beams and a second end provided with a roller which tracks in the channel of an opposed beam.

3,891,108 6 6. A high lift mechanism as defined in claim 1 least one hydraulic cylinder and piston assembly. wherein all of said elements are positioned entirely A high lift mechanism as defined in claim 1 within the confines of said lower and u er frames wherein said fluid actuated ram means comprises at when said upper frames is in its down position.

A high lift mechanism as def-med in Claim 1 5 least two hydraulic cylinder and piston assemblies. wherein said fluid actuated ram means comprises at 

1. A high lift mechanism, for mounting on a truck chassis, to move a cargo body fixed thereto between a retracted, down position and an elevated position comprising, A. a lower frame for fixed engagement with the truck chassis; B. an upper frame to carry the cargo body threatop; C. lever means interconnecting said frames comprised of,
 1. a first combination of levers, and
 2. a second combination of levers; D. fluid actuated ram means for moving said upper frame between said positions; E. means to drivingly engage the extended end of said ram means to said first combination of levers to elevate said upper frame to a predetermined, intermediate, level, in a first phase operation, when pressurized fluid is delivered to said ram means; F. means to disengage said means to engage from said fiRst combination of levers at said intermediate level and to simultaneously engage same with said second combination of levers to elevate said upper frame to its maximum elevated position in a second phase of operation; said interconnecting lever means includes a pair of scissors type lift levers interconnecting each of the respective sides of said upper and lower frames and a link means pivotally attached at a first end to said lower frame, intermediate the opposed ends of said scissors levers; said scissors levers and link means comprising said first combination of levers and said scissors levers comprising said second combination of levers; said means to drivingly engage comprises a bearing plate, fixed to and spanning a portion of one corresponding pair of said scissors levers, and a yoke means at the second end of said link means to receive a tip end portion of said ram; said bearing plate being sized and positioned to maintain said tip end portion in said yoke through said first phase of operation during which forces are directed upwardly by the movement of the ram and the resulting pivotal movement of said link means.
 2. a second combination of levers; D. fluid actuated ram means for moving said upper frame between said positions; E. means to drivingly engage the extended end of said ram means to said first combination of levers to elevate said upper frame to a predetermined, intermediate, level, in a first phase operation, when pressurized fluid is delivered to said ram means; F. means to disengage said means to engage from said fiRst combination of levers at said intermediate level and to simultaneously engage same with said second combination of levers to elevate said upper frame to its maximum elevated position in a second phase of operation; said interconnecting lever means includes a pair of scissors type lift levers interconnecting each of the respective sides of said upper and lower frames and a link means pivotally attached at a first end to said lower frame, intermediate the opposed ends of said scissors levers; said scissors levers and link means comprising said first combination of levers and said scissors levers comprising said second combination of levers; said means to drivingly engage comprises a bearing plate, fixed to and spanning a portion of one corresponding pair of said scissors levers, and a yoke means at the second end of said link means to receive a tip end portion of said ram; said bearing plate being sized and positioned to maintain said tip end portion in said yoke through said first phase of operation during which forces are directed upwardly by the movement of the ram and the resulting pivotal movement of said link means.
 2. A high lift mechanism as defined in claim 1 wherein said means to disengage comprises abutment means fixed to and extending between said bearing plate and said corresponding pair of scissors levers, said abutment means being arranged and positioned to contact the tip end portion of said ram at the end of said first phase, resulting in disengagement of said tip end from said yoke, continued operation of said ram resulting in said second phase of operation during which lifting forces are directed to said upper frame by the scissors levers.
 3. A high lift mechanism as defined in claim 1 including roller means, carried by said tip end portion, in bearing engagement between said yoke and bearing plate.
 4. A high lift mechanism as defined in claim 1 including a spring loaded piston means connecting between said lower frame and link means.
 5. A high lift mechanism as defined in claim 1 wherein the side rails of said upper and lower frames are formed of channel beams, each of said scissors levers having a first end pivotally attached to one of said beams and a second end provided with a roller which tracks in the channel of an opposed beam.
 6. A high lift mechanism as defined in claim 1 wherein all of said elements are positioned entirely within the confines of said lower and upper frames when said upper frames is in its down position.
 7. A high lift mechanism as defined in claim 1 wherein said fluid actuated ram means comprises at least one hydraulic cylinder and piston assembly.
 8. A high lift mechanism as defined in claim 1 wherein said fluid actuated ram means comprises at least two hydraulic cylinder and piston assemblies. 